This report is written mainly for politicians and people working with or administrators of preventive health care. It is hoped that this report may also be of interest to non governmental organizations. The Swedish National Institute of Public Health develops and conveys knowledge for better health.

Low dose alcohol exposure during pregnancy – does it harm?

Women’s social drinking patterns can be difficult to break when planning a pregnancy or when pregnant. Statistics show that 30% of Swedish females continued to drink alcohol during pregnancy. Among researchers there is a consensus about the damaging effect of heavy drinking on the fetus central nervous system. But little is known about low to moderate prenatal alcohol exposure. The Swedish National Institute of Public Health conducted this literature review to examine whether there is an association between low to moderate prenatal alcohol exposure and cognitive and socioemotional development of the child.

Low dose alcohol exposure during pregnancy – does it harm? A SYSTEMATIC LITERATURE REVIEW

R 2009 : 14

The Swedish National Institute of Public Health Distribution SE-120 88 Stockholm

[email protected] www.fhi.se

R 2009:14 ISSN 1651-8624 ISBN 978-91-7257-634-6

Low dose alcohol exposure during pregnancy – does it harm? A SYSTEMATIC LITERATU RE REV IEW

© The Swedish National Institute of Public Health, Östersund 2009, R 2009:14 ISSN:1651-8624 ISBN: 978-91-7257-634-6 Author: Sara Holmgren Cover photo: Photos.com Graphic production: AB Typoform Print: Strömberg, Stockholm, 2009



Contents

4 Preface 5 Summary 6 Sammanfattning Socialt drickande och effekter på foster  6 7 Introduction The prevalence of prenatal alcohol exposure   7 National recommendations for pregnant women   7 Fetal alcohol spectrum disorder  7 The aim  8 9 Method Search method  9 Selection criteria  10 Description of the studies included  11 12 Results Preschool children 3–5 years  12 School children 6–12 years  12 School children 13–16 years  13 16 Discussion Findings?  16 Methodological problems   16 20 Conclusion 21 References 23 Appendix 1. More detailed description of studies included 28 Appendix 2. Excluded studies

Preface

Recommendations to pregnant women concerning alcohol consumption differ between countries. There is a consensus between scholars regarding the damaging effects of heavy drinking on the fetal central nervous systems but little is known about the effects of low to moderate prenatal alcohol. With the child’s health in focus, the Swedish National Institute of Public Health conducted this review in order to contribute to the knowledge on the association between low to moderate prenatal alcohol exposure and cognitive and socioemotional deficits in children. This is the first review examining the association between low to moderate alcohol consumption and cognitive and socioemotional development in children. Results in this review show that half of the studies show a positive association while another half cannot demonstrate such an association. Although these results should be interpreted with caution, care professionals are recommended to advise women to abstain from alcohol consumption during or when planning pregnancy. Sara Holmgren, Swedish National Institute of Public Health had the primary responsibility for the text. Valuable comments have been provided by Sven Bremberg, Swedish National Institute of Public Health, Claes Sundelin, former professor and child specialist at Uppsala University, and Sven Wåhlin, child specialist, and responsible for the Swedish Risk Drinking Project. A survey of the literature search was conducted by Johanna Ahnquist, Swedish National Institute of Public Health. The formal decision to implement this review was made by Director-General Sarah Wamala.

Östersund, September, 2009

Sarah Wamala Director-General Swedish National Institute of Public Health

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L o w d o se alc o h o l e x p o sure durin g pre g nancy

Summary

Regarding the prevalence of prenatal alcohol exposure, statistics show that social drinking during pregnancy is relatively common, 30% of Swedish women continued to consume alcohol during pregnancy. Official recommendations for pregnant women differ between countries. However, there is a consensus among scholars that heavy drinking during pregnancy has damaging effects on the fetal central nervous system. However little is known about the effects of low to moderate doses of prenatal alcohol exposure. With this as a background, the National Institute of Public Health conducted this literature search in order to examine the impact of low to moderate alcohol consumption on children’s cognitive and socioemotional development. Prerequisites for inclusion in the literature review: studies of representative populations, studies that adjust for socioeconomic status, studies that examine low to moderate prenatal alcohol consumption (1–4 glasses of alcohol per week) and studies that examine children between 3–16 years of age etc. Six studies fulfilled the quality requirements and were included in this review. Results show that half of the studies show a positive association while another half cannot demonstrate such an association. However, these studies represent a total of eight analyses distributed between preschool children 3–5 years, school children 6–12 years and schoolchildren 13–16 years. These analyses show that in preschool children, 2 of 3 analyses demonstrate cognitive and socioemotional deficits. Children exposed to prenatal alcohol experience significantly more mental health problems that include hyperactivity/inattention, conduct problems, emotional problems and peer relationship problems as well as being less attentive and experiencing shorter “longest attention episodes”. Such impact was only found in 2 of 5 analyses of schoolchildren 6–16 years of age. From a children’s perspective, it is safest if the mother abstains from social drinking during pregnancy or when planning a pregnancy, since even small to moderate doses of alcohol consumption may have an impact on fetal neurobehavioral development.

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Sammanfattning

Socialt drickande och effekter på foster Många kvinnor har etablerade alkoholmönster som kan vara svåra att bryta vid en graviditet. Statistiken visar att 30 % av de svenska mödrarna fortsätter dricka alkohol under sin graviditet. Det innebär att även relativt små effekter på barnens utveckling är väsentliga ur folkhälsosynpunkt. När det gäller officiella rekommendationer till kvinnor så skiljer sig dessa åt mellan olika länder. Forskarna är eniga om att stora mängder alkoholkonsumtion skadar utvecklingen av fostrets centrala nervsystem. Effekterna av små till måttliga mängder alkoholkonsumtion diskuteras dock fortfarande av forskarna. Med detta som bakgrund har Statens folkhälsoinstitut utfört en systematisk litteraturöversikt där syftet är att undersöka om låg till måttlig alkoholkonsumtion under graviditet påverkar barnets kognitiva och socioemotionella utveckling. Detta har utförts genom att systematiskt gå igenom forskningsartiklar inom området. Under litteraturgenomgången har endast studier som är baserade på en representativ population och som kontrollerar för socioekonomisk status inkluderats. Övriga kriterier är att studierna möjliggör att titta på effekter av låg till måttlig alkoholkonsumtion (1-4 glas alkohol per vecka) samt att studierna undersöker barn i åldern 3 till 16 år etc. Totalt 6 studier uppfyllde kriterierna och är därmed inkluderad i denna systematiska litteraturöversikt. Av dessa visar hälften av studierna på ett samband mellan alkoholintag under graviditet och barnets utveckling. Dessa studier representerar även totalt 8 analyser fördelade över åldersgrupperna: förskolebarn 3–5 år, skolbarn 6–12 år och skolbarn 13–16 år. Analyserna visar att negativa effekter av prenatal alkoholexponering är tydligast i förskoleåldern. När det gäller förskolebarn 3–5 år så visar 2 av 3 analyser på att låg till måttlig alkoholkonsumtion under graviditeten kan leda till kognitiva och socioemotionella problem hos barnet. Barn utsatta för prenatal alkoholexponering uppvisar signifikant fler mentala hälsoproblem så som uppmärksamhetsstörning/ hyperaktivitet, avvikande problem, emotionella problem samt relationsproblem med andra barn. När det gäller skolbarn 6–16 år visade endast 2 av 5 analyser på en sådan påverkan av prenatal alkoholexponering. Från ett barnperspektiv är det säkrast att rekommendera kvinnor som försöker bli gravida och gravida kvinnor att avstå helt från socialt drickande eftersom små till måttliga mängder alkohol kan påverka fostrets neurologiska utveckling.

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Introduction

The prevalence of prenatal alcohol exposure The alcohol consumption among western women in fertile age is increasing. Social drinking may establish a drinking pattern that can be difficult to break when pregnant. In one Swedish study, 30% continued to drink alcohol during pregnancy (1). According to another study, a significant number of the American women continues with alcohol consumption during pregnancy (2). This means that even small effects on the child´s development is relevant from a public health perspective.

National recommendations for pregnant women There is no widely-applied, official recommendation for pregnant women. Depending on country, pregnant women receive different recommendations. In countries like USA and Denmark the official recommendation is strict and governments inform pregnant women or women planning pregnancy to abstain completely from alcohol intake. In Great Britain, in order to minimise the risk to the foetus, the government advises pregnant women never to drink more than one-two units of alcohol once or twice per week and avoid binge drinking. In Australia the government advises pregnant women to abstain from alcohol, but if the woman chooses to drink she should consume less than seven drinks per week, and never more than two drinks on the same day and never get tipsy (3).

Fetal alcohol spectrum disorder There is a consensus between researchers that heavy alcohol drinking during pregnancy may lead to mild to severe fetal alcohol spectrum disorder (2, 4–6). High doses of alcohol intake cause central nervous system dysfunctions in the foetus. A central nervous system dysfunction may include neurological anomalies, delayed mental development, an alteration of cognitive functioning and behavioural problems. It may also include structural anomalies such as microcephaly or brain malformations; in addition it also has a damaging effect on morphogenesis and growth (5, 7). A study conducted on Italian schoolchildren shows that the prevalence of Fetal alcohol spectrum disorder (FASD) is about 3 percent (24). Even low doses of prenatal alcohol exposure have been linked to adverse psychological and neurodevelopment outcomes without any structural abnormalities. This includes deficits in cognitive performance and psychosocial functioning (2).

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Studies in animals indicate that consumption corresponding to 1-2 drinks a day might affect the foetus (25). Yet, findings in animal studies might not easily translate into humans. Thus, there is no consensus of the effects of low doses of alcohol. Consequently, it is vital to establish the effect of low to moderate alcohol exposure on children. Furthermore, from a public health perspective it is important to establish health effects of alcohol consumption during pregnancy. A Swedish study demonstrated long-run consequences of prenatal alcohol exposure. At the age of 30 people who hade been prenatally exposed had lower educational attainments, lower earnings and higher welfare dependency rates than their peers. This result suggests that investments in early-life health may both be a more humane and a more effective way of increasing human capital accumulation in comparison with later life investments (26).

The aim The aim of this systematic literature review is to examine the association between low to moderate prenatal alcohol exposure and cognitive and socioemotional deficits in children.

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Method

The purpose of this systematic review is to synthesise results from a large number of published articles. Relevant articles on prenatal alcohol exposure were identified through search strings in databases and selection criteria. If the articles matched the selection criteria they were included. This increased opportunities to identify and include high quality articles which is important for credible conclusions.

Search method The studies included in this review were obtained by the following literature search, see table 1. The search strings were run in the databases PubMed, Psych Info and ERIC on 22 june, 2009. Table 1. Literature search on prenatal alcohol exposure Search strings

Database

Number of hits

(“Alcohol Drinking”[Mesh] OR alcohol*[Title/Abstract] AND (“Pregnancy Trimesters”[Mesh] OR pregnancy[Title/Abstract] OR fetal[Title/ Abstract] OR prenatal[Title/abstract]) AND (“Cohort studies”[Mesh] OR cohort[Title/Abstract])

PubMed

937

((DE ”Alcohol Abuse” or DE ”Alcohol Drinking Patterns” or DE ”Alcohol Intoxication” or DE ”Alcoholism”) and (DE ”Prenatal Exposure”)) and (DE ”Longitudinal Studies”)

PsychInfo

6

(Drinking or alcohol) and KW=(Pregnancy or (Prenatal influences)) and KW=longitudinal studies

ERIC

11

KW=Drinking and KW=(Pregnancy or (Prenatal influences))

ERIC

8

A second reviewer has reviewed the search strings applied in this review.

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Selection criteria The studies were included in this review if they fulfilled the following selection ­criteria: • Publication in a scientific, peer-reviewed journal. • Examination of the offspring’s cognitive and socioemotional development. • Examination of low to moderate prenatal alcohol intake (i.e. 1-4 glasses per week or 12-48g of alcohol intake per week). • Prospective studies. • The study design was longitudinal, randomised or quasi-randomised controlled trials. The follow-up time of the children was between 3–16 years of age. • The study describes their method and design. Studies that refer to other articles only are excluded. • A control of socioeconomic status (ex. education, occupation, income) is included in the analyses, alternatively a determination of no statistical difference between the groups of no versus low alcohol intake. • Representative population. There is no broad consensus regarding the definition of light to moderate levels of alcohol intake (8). However, the definition of a light to moderate drinker in this review is a pregnant woman who consumes 12–48g of alcohol per week. This is equal to 1-4 standard drinks per week (AUDIT). Since the focus is the cognitive and socioemotional development of the child, only studies that have examined children at aged 3 and above have been included. The argument behind this decision is that it is not possible to examine the effects on children at an early age since the appearance of symptoms and the development of cognitive functions mature later. The children concerned may show flaws regarding learning ability, attention and memory functions at school age (3). High risk samples of mothers are excluded because the aim is to generalise to the wider population. Clinically diagnosed samples of children were also excluded.

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Description of the studies included The literature search on prenatal alcohol effects generated 962 articles. The abstracts of these papers were analysed. Of these, 65 articles were found to be potentially relevant and were therefore studied in full. This generated 6 articles that fulfilled the inclusion criteria. The studies derive from US, England, Denmark, Finland and Australia. The child outcomes examined are intellectual ability, attention, memory and learning abilities, behavioural and emotional problems. Only three studies examined whether boys or girls are affected differently by prenatal alcohol consumption (9, 10, 11). Three studies apply response categories regarding maternal alcohol intake (9, 10, 12), in addition three studies applies the AA Score which yields the average daily ounces of absolute alcohol consumed (11, 13–14). Effects of prenatal alcohol exposure can be detected from both types of alcohol intake reports. The sample size in the studies varies between follow-up data from 128 women to 9086 women. The attrition rate varies between 18–48 percent. One study has performed sensitivity measurements in order to examine the effects of attrition (9). This study concluded that a minor increase in the strengths of the association between